Warning light



Aug. 8, 1961 H. F. ZIMMERMAN 99573? WARNING LIGHT Filed June 5, 1957 2 Sheets-Sheet 1 \////Af/,///// V0 Filed June 3, 1957 2 Sheets-Sheet 2 'Il-'HP INVENTOR. HAROLD 'Z//Y//WVIV United States 2,995,737 Patented Aug. 8, 1961 2,995,737 WARNING LIGHT Harold F. Zimmerman, 221 Gul Ave., 'Louisville 12, Ky. Filed June 3, 1957, Ser. No. 663,315 3 Claims. (Cl. 340-366) (Granted under Title 35, U.S. Code (1952), sec. 266) The invention described herein may be manufactured and used by or for the United States Government for governmental purposes without payment to me of any royalty thereon.

This invention relates to warning or indicating lights as commonly employed to show a condition at some remote point out of View of an operator and more particularly to'` warning or indicating lights on the panel of an airplane or ship. On shipboard, and especially in an airplane, it is necessary for the pilot to know whether the various indicating devices are in working order and to know whether the indicating lights are burned out or not. Since there are many indicators to be checked, it is desirable that tests be quick and simple. It is `also desirable to? be able to dim any light indicating device so that at night the pilots vision will not be impaired by the bright glow of a warning bulb.

There have been devices which will show the condition of the bulb filament by pressing in on the light bulb assembly, and some to dim the light bulb by adjusting a series resistance or changing the position of a shutter by a separate motion, but none that require merely the Same simple press-in motion to both test the bulb and dim the light. Once the dim condition has been established, it remains as a warning to the pilot and cannot be disestablished until the remote switch is opened. It will not be affected by changes in ambient temperature or by vibration since the solenoid action is not influenced by temperature and the spring pressure keeps all parts in place and assures good electrical contact.

It is an object of this invention to provide a simple and quick test for the condition of the pilot bulb and at the same time provide an equally quick and simple means to dim the light when it is desirable.

It is also an object of this invention to provide a dimming actio'n which will not be affected by changes in atmospheric pressure or in ambient temperature or by vibration and which will maintain good electrical contact at all times.

FIGURE l is a vertical sectional view of a preferred embodiment showing it in normal or ready position, with all contacts closed except the bulb test contact;

FIGURE 2 is a schematic view showing the position of the parts when the bulb is being tested, yand at a remote point an open switch 40 which can be closed 'when the gasoline tank is empty or nearly so; and

FIGURE 3 is a schematic View showing the position of the parts after the circuit is energized by the closing of a remote switch 40', when the landing gear s retracted, and the bulb has been depressed for the dimming action.

In these -iigures, the numeral indicates a light lter or lens in a standard light lter assembly 11, which is attached to the light bulb housing, or assembly, 12. The light bulb assembly 12 contains the bulb 13 held by the lamp socket 15 (shown to accommodate a' bayonet type bulb, but which could be adapted to hold any other type bulb, such `as a screw type), the compression coil spring 16 which holds the lamp and its socket 15 in place, the compression coil spring 17 which 'forces the contact pin 18 against the bottom contact of the bulb, the metal tube or collar 20 which supports and acts as a guide for contact pin 1'8 and carries electrical contact 36, half of contact 22, and half of wiping contact switch 37. The guide 20 is insulated from the other parts of the housing by insulation 19 so that it carries current to the bottom contact of the bulb only through switch 37, contact 436, or contact 22. The light bulb assembly 12 is held in place by compression coil spring 21 and is contained in the outer case or container 14 and is free to move in a longitudinal direction against the pressure of coil spring 21 until it is stopped by insulation tube 23. Numeral 23l designates a Bakelite or plastic insulating tube containing solenoid coil 29, serving as a stop for light assembly 12,` a guide for spring 21 and carrying contacts 22, 24, 26, 34, 35 and half of wiping contact 37.

Solenoid plunger 28 is a soft iron rod free to move in solenoid 29 against the pressure of spring 31 and carries two metal discs 25 and 27, insulated from each other, which make electrical contact with contacts 24, 26, 34 and 35.

Lead 32 is one terminal of solenoid coil 29 and is attached to contact 34 which is attached to lead 38.

Lead 33 is the other terminal of the solenoid and is attached to one side of wiping switch 37. The numeral 41 designates an electrical connection which completes the circuit for the bulb test through contact 24 and bulb test lead 39. The numeral 38 is the lead from the remote control point land is shown in FIGURE l running to one side of an open switch 40y which closes when the gasoline is low in the tank.

To test the bulb it is merely necessary to press in on the iilter assembly which breaks contact 22 and completes the circuit through contact 24, contact carrier 25 and contacts 35 and 36 causing the lamp to glow brightly as shown in FIGURE 2. Upon release, the assembly returns to the ready position, contact 36 is opened, and the' lamp goes out.

When the remote indicator circuit is closed through switch 40 or 40', current o'ws through contact 34, through contact carrier 27 to contact 26, and through contact 22 to the lamp ywhich will glow at full brilliance.

To dint the light, the bulb is depressed as for bulb test, contact 22 is broken, contact 36 is made keeping the lamp at full brilliance but upon release contact 36 is broken before contact 22 is made and current flows through coil 29 which has been shorted out by the low resistance contacts, thus energizing it so that rod 28 is pulled by electromagnetic action to the down position opening contacts 24, 26, 34 and 35. This puts the resistance o'f the solenoid coil in series with the lamp filament, thus causing the kbulb to glow lat reduced brilliance. This condition will continue until the remote indicator circuit is deenergized by opening the remote switch.

What I claim is:

l. lIn a warning light system comprising a source of electrical energy, a solenoid unit comprising a coil and an armature, lan indicating lamp adapted for movement between two positions, a' rst electrical circuit including a portion of said armature connecting said source of electrical energy with said lamp when said lamp is in one of said two positions, a second electrical circuit having a switch therein and including a second portio'n of said armature insulated from said inst-mentioned portion, said second electrical circuit connecting said source of electrical energy with said lamp when said switch is closed land said lamp is in the other of said two positions, said coil having a connection at one end to said lamp and at its other end to said second electrical circuit such that said coil is in an open circuit when said lamp is in the said one of said two positions and said switch is open and shorted by said second portion of said armature when said lamp is in the other of said two positions, and means operated by movement of said lamp between said two positions for disconnecting said rst and second circuits from said lamp thereby allowing energization of said coil when said switch is closed to operate said armature, said operation of said armature causing an opening of both said rst and second electrical circuits such that said coilv is in series with said source, said switch and said lam-pto dim said lamp when said lamp is in the other of said two positions.

2. In a warning light system a source of electrical energy, a lamp adapted for movement between vtwo posi tions, a solenoid unit comprising a coil and an armature, a rst electrical circuit comprising an electrically .conductive portion of said armature, a switch; connected between said first electrically conductive portion of said armature and said source and means connecting said first electrically conductive portion of said armature to said lamp when said lamp is in one of said two positions, a second electrical circuit including a second electrically conductive portion of said amature connected between said source and said lamp when said lamp is in the other of said two positions, said coil of said solenoid unit having eine end thereof connected to the connection of said switch and ai. t

said lirst electrically conductive portion and the other end thereof being Iconnected to said lamp such that said rst conductive portion shorts said coil when said lamp is in said one of said positions and unshorts said coil when said lamp is in the other of said positions and said switch is open, and means operated by movement of said lamp between said two positions for allowing energization of said coil when said switch is .closed thereby actuating said armature to break both said `first; and second circuits to leave said coil in series with said source, said switch and said larnp when said lamp is in the irst of said two' positions.

3. A system as defined in claim 'Z wherein said coil is shorted by said switch when said lamp is in the other .of said two positions and said switch is closed.

References Cited in the file of this patent UNITED 'STATES PATENTS Hallenberg Ian. l0, 1956 

